Oil Stains and Tire Marks on a Concrete Driveway
Dark spots where the car sits and black tire marks where it parks are two different stains. What causes each one, how they come up, and when a stain will not fully go.
The short answer
Oil spots are motor oil soaked into the pores of the concrete. Tire marks come from chemicals in the tire rubber moving onto the slab when a hot tire sits still. Both are oil based, so a degreaser plus high pressure cold water lifts most of it. Old, deep oil stains can lighten rather than disappear.
Two stains that look alike
From the street, a driveway with dark marks looks like one problem. Up close it is usually two.
- Oil spots sit where a car leaks: a dark, soft-edged blotch, often in the middle of the parking spot.
- Tire marks sit right where the tires stop: black stripes or patches the shape of the tread, usually on the part of the drive closest to the garage.
They have different causes, but they come off in a similar way.
Where tire marks come from
RadonSeal, a company that makes concrete sealers and cleaners, explains tire marks as “plasticizer migration.” Driving heats the tire. When the car parks, chemicals from the softened rubber leach out of the tire and onto the concrete. It calls this the main reason concrete gets tire marks (RadonSeal).
That is why the marks build up in the one spot where you pull in every day.
Why oil soaks in
Concrete is porous, which is the same reason shaded slabs hold water and grow mildew (see growth on concrete patios). Motor oil does not sit on top. It wicks down into the pores, and the longer it sits, the deeper it goes. That is why a spot that has been there for years is harder to lift than a new one.
How they come up
Both stains are oil based. RadonSeal says the cleaners that work best on tire marks are the ones made for removing oil, applied so the area stays wet, given time to break the bond with the concrete, scrubbed and rinsed (RadonSeal).
Our method on driveways, sidewalks and walkways follows the same idea at a larger scale. Flatwork is the one place we use high pressure: cold water at high pressure on concrete, asphalt and paver drives, with a degreaser added when the surface needs it, which is most of the time where cars park. Oil spotting, tire marks, dirt and the gray organic film all come up in the same visit.
What to expect from an old stain
Newer stains sit closer to the surface. A stain that has soaked in for years can fade to a lighter shadow rather than disappear. We look at it first and tell you what to expect before we quote.
Businesses and parking areas
Oil and tire marks show up on business concrete too. Commercial flatwork is scheduled around your business hours. See commercial pressure washing.
What cleaning will not fix
Oil that has soaked in for years can leave a shadow even after a good cleaning, and we will tell you that before we start rather than promise it vanishes. Cleaning will not fix cracks, pitting or sealer that has worn unevenly, and a stain that keeps coming back usually means a car is still leaking.
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